Question

In several substations around the world, copper (Cu) cables are used to connect transformers to LV boards, while aluminium (Al) cables are used to connect the LV boards to the consumers. I heard that bimetallic washers are used to connect those two types of cables, that have different conducting materials.

Can you please how Al and Cu cables connected with each other, and what is the science behind it?

Answer 1

Ans)

In practice aluminium is resistant against corrosion but it is a highly-reactive and readily-oxidising material If conductive liquid that is condensate or water enters an aluminium and copper connection, an electrochemical reaction occurs and causes contact element formation

then condensate /water acts as electrolyte and copper acts as anode and alluminium acts cathode form an electro chemical process cause potential difference between copper an alluminium ,This potential/voltage shorted by contact in between two metals this burst of short circuit cause current to flow which causes alluminium to decompose or deposits which inturn leads to fire or damage of alluminium

therfore care must be taken while joining copper and alluminium i.e prevent the influx of moisture at the junction of the two materials and point of contact between two metals is protected by special processing methods